I just competed in this one last Saturday. I did fairly well (won my division in gi, took 3rd in no-gi). Just so we're on the same page, I'm a 3 stripe blue with 4ish years of grappling experience. I have competed in 3 tourneys total with no time limit.

First off, what is your ruleset? All of the ones I've seen here in the northwest are very liberal. The tourney from last Saturday allowed all grips, all submissions. There was literally nothing illegal (contrary to the rules posted on the site).

I have a few recommendations that I feel helped me:

-Train with an advanced belt in position-only rolling in 20-minute rounds. You will get dominated positionally, and have to work on just staying safe in bad positions. One thing I saw a lot on Saturday was people making desperate attempts to get out of a bad position, when they weren't in imminent danger. Take your time and stay safe, and your opponent will give you an opening.

- Work on maintaining positions with the most explosive guys in your gym. You can really use dominant positions to drain someone with no time limit, and it will let you conserve your energy for later matches.

- Focus very heavily on your breathing and relaxation while rolling. If you wear yourself out, your opponent will capitalize.

- I'm typically very takedown aggressive. In these tournaments, I was very passive. It doesn't matter who gets the takedown, as long as you don't give up dominant position. I was taken down twice into guard, and they were burning energy much faster than I was.

- You will probably notice a much more "active" experience in this tournament. Since stalling does no good, opponents are constantly looking for submissions, instead of maintaining a point lead.

Those are my big ones. Other than that, be aware that failing submissions that give up position can be devastating to you.

My matches were all very short (longest was 6 minutes), and my longest ever is about 7 minutes. My wife has had two 30-minute matches, though, so you have to be in shape in case that happens.